The present invention relates to a disk apparatus for recording or reproducing information on/from a disk-like recording medium.
Hitherto, disk apparatuses for recording/reproducing information on/from disk-like recording media (hereunder referred to as recording disks), for example, CD-ROMs and CD-Rs have been widely used. The disk apparatus has a spindle motor for rotating and driving a recording disk, and a recording/reproducing head for recording/reproducing information by irradiating laser light or applying an external magnetic field to an information recording face of a disk-like recording medium. Further, the disk apparatus is constructed so that a recording disk is freely attachable to and detachable from a chucking table attached to the rotary shaft of the spindle motor.
Hitherto, such disk apparatuses have been mounted on various kinds of computer systems, and utilized as external storage devices. However, in the case that such a disk apparatus is mounted on a small apparatus, such as a notebook computer having been coming into wide use in recent years, more miniaturization and thickness reduction are demanded of the disk apparatus.
Meanwhile, the chucking table of a related disk apparatus has a structure as illustrated in, for example, FIG. 6.
That is, a chucking table 100 comprises a support 102, which is formed like a disk, for supporting the bottom face of a recording disk 101, and a cover 103 coaxially integrated with the support 102. The cover 103 is formed with a bearing part 103a to be fitted with this rotary shaft 104a, and an abutment part 103b that abuts against an inner periphery 101a of the recording disk 101. Further, the support 102 and the cover 103, which are in an integrated state, are fixed to the rotary shaft 104a of the spindle motor 104 such that the bearing part 103a extends along the rotary shaft 104a. 
Further, the chucking table 100 has a claw portion 105 projected from the abutment part 103b. This claw portion 105 outwardly pushes the inner periphery 101a of the recording disk 101 in the radial direction thereof by a spring member 106 disposed between this claw portion 105 and the bearing part 103a to thereby retain the recording disk 101 on the chucking table 100.
However, the chucking table 100 of such a structure needs to reduce the thickness of the support 102 indicated by an arrow A in FIG. 6 for the purpose of reducing the thickness so that the distance between the recording disk 101 and the spindle motor 104 is narrow. In such a configuration, it is extremely difficult to attach the support 102, which is formed in such a way as to be thin, to the rotary shaft 104a in such a manner as to be perpendicular thereto. Therefore, the assembling accuracy of the disk apparatus is degraded. It is difficult to enhance the production efficiency. Moreover, when the support 102 (thus, the chucking table 100) is obliquely attached to the rotary shaft 104a, axial runout occurs in the recording disk. Thus, it is impossible to perform normal recording/reproducing operations.
Thus, it is considered that a bearing part 102a is provided in range with and formed along a part extending from the support 102 to the rotary shaft 104a, as shown in, for example, FIG. 7, to thereby enhance the accuracy in attaching the support 102 to the rotary shaft 104a. However, in this case, since the cover 103 abutting against the recording disk 101 is attached to the rotary shaft 104a through the bearing part 102a of the support 102, the assembling accuracy of the cover 103 with respect to the rotary shaft 104a tends to be degraded. Accordingly, the recording disk 101 is not accurately mounted on the chucking table 100 coaxially with the rotary shaft 104a, and that it is, thus, difficult to perform a normal recording/reproducing operation.